As a plasma generating device, a capacitively coupled plasma source and an inductively coupled plasma source and helicon using a plasma wave and a microwave plasma source are generally proposed. Among them, the inductively coupled plasma source which can easily form high-density plasma is widely used.
FIG. 1 illustrates an inductively coupled plasma generation device and in the inductively coupled plasma generation unit 10, a substrate to be processed is mounted on a substrate holder 16 in a receiving space in a chamber 15, reaction gas is supplied into the chamber, and an antenna 17 connected with an RF power source is installed on the upper portion of the chamber 15, and as a result, when power is applied to the antenna 17 from an impedance matched RF power source, RF power, that is, an RF potential and current are applied to the antenna 17. The applied RF potential forms an electric field which varies according to a time in a direction parallel to a dielectric isolating the antenna 17, the RF current that flows on the antenna 17 forms a magnetic field in an inner space of the reaction chamber 15, and an inductive electric field is formed by the magnetic field.
In this case, the reaction gas in the chamber 15 acquires sufficient energy required for ionization from the inductively generated electric field to form plasma. The formed plasma is injected into the substrate installed in the substrate holder 16 to process the substrate. The plasma is generally referred to as inductively coupled plasma (ICP) and a device using the same is referred to as an inductively coupled plasma processing device.
It is preferred to increase a plasma density by considering a throughput of a plasma processing process and pressure lowering of a process for overcoming a contaminated particle generation problem and a scheme is presented, in which since the density of the plasma formed in the chamber 15 is further increased by an inductive electric field by a magnetic field than the electric field formed in the chamber 15, a permanent magnet is disposed outside the chamber 15 in order to further increase the plasma density to include multiple magnetic field generation units 11, 12, and 13 (Korean Patent Unexamined Publication No. 10-2009-37343).
However, in the case of the plasma processing device using the magnetic field regardless of the permanent magnet or an electromagnet using a coil, it is difficult to uniformly control the plasma densities of the center and the outer periphery of the inner space of the chamber, and as a result, reliability of a product quality by performing the plasma processing process may deteriorate and for example, the density of the plasma decreases in proportion to the distance in the outward direction from the center of the chamber during the plasma processing process of the substrate, and as a result, the plasma is not appropriately processed, thereby causing a fault and in particular, non-uniformity of an etching or deposition process due to non-uniformity of the plasma density may be a more serious problem while processing a large-area substrate.
Therefore, a scheme that can increase uniformity of the plasma density throughout the center and the outer periphery of the substrate while acquiring a high plasma density is required in the inductively coupled plasma device using the magnetic field.